We know decreasing animal product consumption decreases our IGF-1 levels, but how low do we have to go? How plant-based does our diet need to get? In my 2-min. video How Plant-Based to Lower IGF-1? the IGF-1 levels are compared between men and women eating conventional, vegetarian, and vegan diets. Only the vegans had significantly lower levels.

Vegan men tended to have significantly higher testosterone levels than both vegetarians and meateaters (see graph here), which can be a risk factor for prostate cancer, the reason plant-based diets appear to reverse the progression of prostate cancer may be due to how low their IGF-1 drops (see Cancer Reversal Through Diet?).